Monitoring and correction of multiple scatter during clinical Compton scatter densitometry measurements

Mooney, Michael; Naga, S; Speller, Robert; Koligliatis, T

doi:10.1088/0031-9155/41/11/011

Cited by 8 publications

(4 citation statements)

References 6 publications

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“…For simple geometries multiple scatter may be predicted and subtracted from the total signal to yield single scatter using an approach that has been used in Compton densitometry applications. 27 To use a multiple scatter subtraction technique, the distribution of multiple scatter for the imaging geometry in question is required. In the case of breast tomography, there are two factors that work in favor of predicting a multiple scatter distribution:…”

Section: Multiple Scattermentioning

confidence: 99%

“…The single scatter is treated as signal instead of noise, increasing the signal to noise ratio as a result. Multiple scatter can be removed using a subtraction technique, 27 and contrast will be increased as a result of an increase in "information carrying" photons. 28 This could be used to enhance the sensitivity and specificity of CT imaging for the early detection of breast cancer.…”

Section: Introductionmentioning

confidence: 99%

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An iterative three‐dimensional electron density imaging algorithm using uncollimated Compton scattered x rays from a polyenergetic primary pencil beam

2006

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X-ray film-screen mammography is currently the gold standard for detecting breast cancer. However, one disadvantage is that it projects a three-dimensional (3D) object onto a two-dimensional (2D) image, reducing contrast between small lesions and layers of normal tissue. Another limitation is its reduced sensitivity in women with mammographically dense breasts. Computed tomography (CT) produces a 3D image yet has had a limited role in mammography due to its relatively high dose, low resolution, and low contrast. As a first step towards implementing quantitative 3D mammography, which may improve the ability to detect and specify breast tumors, we have developed an analytical technique that can use Compton scatter to obtain 3D information of an object from a single projection. Imaging material with a pencil beam of polychromatic x rays produces a characteristic scattered photon spectrum at each point on the detector plane. A comparable distribution may be calculated using a known incident x-ray energy spectrum, beam shape, and an initial estimate of the object's 3D mass attenuation and electron density. Our iterative minimization algorithm changes the initially arbitrary electron density voxel matrix to reduce regular differences between the analytically predicted and experimentally measured spectra at each point on the detector plane. The simulated electron density converges to that of the object as the differences are minimized. The reconstruction algorithm has been validated using simulated data produced by the EGSnrc Monte Carlo code system. We applied the imaging algorithm to a cylindrically symmetric breast tissue phantom containing multiple inhomogeneities. A preliminary ROC analysis scores greater than 0.96, which indicate that under the described simplifying conditions, this approach shows promise in identifying and localizing inhomogeneities which simulate 0.5 mm calcifications with an image voxel resolution of 0.25 cm and at a dose comparable to mammography.

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Section: Multiple Scattermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An iterative three‐dimensional electron density imaging algorithm using uncollimated Compton scattered x rays from a polyenergetic primary pencil beam

2006

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“…The size of the phantom also determines the probability of its occurrence. Mooney et al (1996) corrected the bias attributed to multiple scatter by introducing multiple scatter correction function (mcf).…”

Section: Multiple Scatteringmentioning

confidence: 99%

Electron density of Rhizophora spp. wood using Compton scattering technique at 15.77, 17.48 and 22.16keV XRF energies

Shakhreet

Bauk

Shukri

2015

Radiation Physics and Chemistry

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“…We recall the use of the information of the transmitted beam to determine the attenuation coefficient, or the use of collimators to define a small region of interest in the examinated object in order to reduce the multiple scatter component. Also the Monte Carlo approach has proven to be able to provide corrections for this source of background [19,7]. In this paper we want to further explore the potential of the novel method to image the electron density in the human body proposed in [1] by means of a detailed Monte Carlo (MC) simulation using GEANT4 [20] with a realistic set-up.…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo study of a 3D Compton imaging device with GEANT4

Lenti

Veltri

2011

Nuclear Instruments and Methods in Physics Research Section A:

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In this paper we investigate, with a detailed Monte Carlo simulation based on Geant4, the novel approach of Lenti (2008) [1] to 3D imaging with photon scattering. A monochromatic and well collimated gamma beam is used to illuminate the object to be imaged and the photons Compton scattered are detected by means of a surrounding germanium strip detector. The impact position and the energy of the photons are measured with high precision and the scattering position along the beam axis is calculated. We study as an application of this technique the case of brain imaging but the results can be applied as well to situations where a lighter object, with localized variations of density, is embedded in a denser container. We report here the attainable sensitivity in the detection of density variations as a function of the beam energy, the depth inside the object and size and density of the inclusions. Using a 600 key gamma beam, for an inclusion with a density increase of 30% with respect to the surrounding tissue and thickness along the beam of 5 mm, we obtain at midbrain position a resolution of about 2 mm and a contrast of 12%. In addition the simulation indicates that for the same gamma beam energy a complete brain scan would result in an effective dose of about 1 mSv

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Monitoring and correction of multiple scatter during clinical Compton scatter densitometry measurements

Cited by 8 publications

References 6 publications

An iterative three‐dimensional electron density imaging algorithm using uncollimated Compton scattered x rays from a polyenergetic primary pencil beam

An iterative three‐dimensional electron density imaging algorithm using uncollimated Compton scattered x rays from a polyenergetic primary pencil beam

Electron density of Rhizophora spp. wood using Compton scattering technique at 15.77, 17.48 and 22.16keV XRF energies

Monte Carlo study of a 3D Compton imaging device with GEANT4

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